Official Luthiers Forum!

Owned and operated by Lance Kragenbrink
It is currently Thu Mar 28, 2024 2:32 pm


All times are UTC - 5 hours





Post new topic Reply to topic  [ 5 posts ] 
Author Message
PostPosted: Sat Dec 19, 2015 3:00 am 
Offline
Cocobolo
Cocobolo
User avatar

Joined: Fri Dec 01, 2006 6:44 pm
Posts: 471
Location: Australia
First name: Allen
Last Name: McFarlen
City: Mt. Sheridan
State: Qld.
Zip/Postal Code: 4868
Country: Australia
Focus: Build
Status: Professional
Designing some vacuum jigs and wondering how deep I should rout for 5.5mm diameter cord? It's probably some imperial size, but I work in metric.

I recall reading some time ago that you need room for the cord to compress into, so I was thinking a 5mm wide square shoulder trench and perhaps 4mm deep.

_________________
Allen R. McFarlen
Barron River Guitars & Ukuleles
Facebook
Cairns, Australia


Top
 Profile  
 
PostPosted: Sat Dec 19, 2015 12:59 pm 
Offline
Contributing Member
Contributing Member
User avatar

Joined: Thu May 12, 2005 5:46 am
Posts: 2931
Location: United States
Allen, Yes, you need room for the O-ring to compress into. You want the work piece making contact with the fixture not setting up on the cord. FWIW, I use 1/8" cord and use a 1/8 wide X .085 groove. Also, it helps to use a low durometer cord stock for this application and use some CA glue to bond the ends of the cord stock together to prevent leaks there.
You might try searching for the Parker O-ring hand book for more information on O-ring grooves.

_________________
Jim Watts
http://jameswattsguitars.com


Last edited by Jim Watts on Sat Dec 19, 2015 2:47 pm, edited 3 times in total.

Top
 Profile  
 
PostPosted: Sat Dec 19, 2015 1:29 pm 
Offline
Walnut
Walnut

Joined: Sat Feb 14, 2015 3:06 pm
Posts: 6
First name: Scott
Last Name: McKee
City: Cumberland
State: BC
Zip/Postal Code: V0R 1S0
Country: Canada
Focus: Build
Status: Semi-pro
From an older post by Bob Garrish in this thread:
http://www.luthiersforum.com/forum/viewtopic.php?f=10106&t=38998

So far as parameters for the cord go, always use a flat bottomed channel at full gasket diameter and cut ~60-70% of diameter for depth and you won't have any issues with the gasket sinking in perfectly. I use 3/16" gasket and cut channels at 0.110", and no problems have ever been the gasket's fault.

I've found that round cord in a square channel at 70% of gasket diameter in depth has worked well for me

Scott


Top
 Profile  
 
PostPosted: Sat Dec 19, 2015 3:31 pm 
Offline
Cocobolo
Cocobolo
User avatar

Joined: Fri Dec 01, 2006 6:44 pm
Posts: 471
Location: Australia
First name: Allen
Last Name: McFarlen
City: Mt. Sheridan
State: Qld.
Zip/Postal Code: 4868
Country: Australia
Focus: Build
Status: Professional
Thanks. I'll get out the calculator and work out the depth.

_________________
Allen R. McFarlen
Barron River Guitars & Ukuleles
Facebook
Cairns, Australia


Top
 Profile  
 
PostPosted: Sun Dec 20, 2015 8:25 pm 
Offline
Brazilian Rosewood
Brazilian Rosewood
User avatar

Joined: Tue May 02, 2006 9:02 am
Posts: 2351
Location: Canada
First name: Bob
Last Name: Garrish
City: Toronto
State: Ontario
Country: Canada
Status: Professional
What Scott said. And what Jim said.

Get the mushy neoprene foam stuff (Allstar Adhesives and McMaster both have it) and the round stuff works better. I used to glue the ends together, but now I just cut the cord a little long so the ends are compressed together in the groove a bit. Both ways work fine.

_________________
Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 5 posts ] 

All times are UTC - 5 hours


Who is online

Users browsing this forum: No registered users and 12 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  
Powered by phpBB® Forum Software © phpBB Group
phpBB customization services by 2by2host.com